The objective is to perform a feasibility and exploratory study of the biochemical epidemiology of prostate cancer in black and white patients in New York City in which selected hormones will be assayed in both serum and prostatic fluid. Interviews will be conducted with cases and controls to collect data on known and suspected risk factors for prostate cancer. The two control groups, frequency-matched by hospital, race and age, will consist of patients without prior history of malignancy from general surgical services other than urology, and patients with histologically confirmed benign prostatic hyperplasia. Levels of estradiol, estrone, testosterone, dihydrotestosterone and prolactin will be determined by radioimmunoassay. In addition, prolactin will be measured by the rat Nb2 lymphoma cell bioassay, the molecular forms studied, and comparisons made of the bioassayable and radioimmunoassayable levels of prolactin in both cases and controls. The results of hormone assays of prostatic fluid will be correlated with those of serum, and with known and suspected epidemiological risk factors in the various case-control subgroups. The goal is to define a new approach to the study of prostate endocrinology and, ultimately, to apply this to an in-depth international investigation of biochemical epidemiology in black and white populations of differing levels of prostate cancer risk.